IN-VIVO FACILITATION OF TETRAHYMENA GROUP-I INTRON SPLICING IN ESCHERICHIA-COLI PRE-RIBOSOMAL-RNA

The observation that the large ribosomal RNA intron of Tetrahymena is spliced 20-50-fold more rapidly in vivo than in vitro (Brehm SL, Cech TR, 1983, Biochemistry 22:2390-2397; Bass BL, Cech TR, 1984, Nature 30 8:820-826) suggests facilitation of RNA folding in vivo. To determine whether a specific group I splicing factor is required in Tetrahymena, the intron was inserted into the analogous position of the Escherichi a coli 23S rRNA. We report that the intron is rapidly excised from pre -rRNA in bacteria and that the magnitude of the in vivo rate enhanceme nt is similar to that in Tetrahymena. These results demonstrate that a species-specific protein is not required. Instead, a common mechanism of assisting RNA folding is sufficient to accelerate the removal of s elf-splicing introns from ribosomal RNA.